The overall goal of this project is to investigate the relationship between the globoside-Forssman isoantigenic system and the occurrence of various types of adenocarcinoma in humans in order to determine if there is a basis for attempting specific immunotherapy of some cancer patients using Forssman (Fs) antigen. In this project, tumor and normal tissue will be obtained from patients with gastric, colon or breast adenocarcinoma. The tissue will be lyophilized and will then be tested by antibody absorption in order to determine if the tumor and or the normal tissue contains Fs antigen. In addition, sera from patients with different stages of disease will be tested for Fs antibody in order to determine if there is a relationship between the level of Fs antibody and tumor recurrence or metastases. The class of Fs antibody (i.e. IgM and/or IgG), in healthy people and in adenocarcinoma patients with various stages of disease, will also be determined. In addition, we will test by antibody absorption the white cells of normal individuals for the presence of Fs antigen. If Fs antigen is present on white cells, the test will enable the Fs antigen status of humans to be readily determined and will enable us to confirm the existence of a reciprocal relationship between Fs antibody and Fs antigen. Since the Fs antigen status of the tumor and the level of Fs antibody in the serum may be affected by the formation of immune complexes, we will determine if circulation immune complexes (IC) are present in the sera of patients with adenocarcinoma. If ICs are found, they will be characterized and the complement status of the patients will be determined.